MarketWatch's Corporate Tax Calculator:

Look up what S&P 500 companies pay in taxes

Methodology: Companies’ effective income-tax rates can change from quarter to quarter and year to year because of major accounting adjustments and events. Examples include asset write-downs, gains or losses on sales, realization of deferred tax assets and legal settlements. Effective income-tax rates also include state and local income taxes paid, if any. The median effective income-tax rate is calculated using data from the past 11 years of annual 10-K filings with the Securities and Exchange Commission. The effective median income-tax rate is not available for companies with fewer than five years of data.

The median for sectors calculated by FactSet excludes any companies annual income-tax rates that were above 100% or below 0%.